Salivary glycoproteins are now recognized as having a significant role in the ecology of the oral cavity. The ability of these glycoproteins to aggregate oral bacteria is of particular importance since this interaction is believed to be involved in the accumulation of dental plaque. It has not been determined whether the carbohydrate and/or protein moieties of these glycoproteins are involved in this aggregation. The purpose of this investigation is to determine which portion of the salivary glycoprotein molecule is involved in the biomolecular interaction with oral microorganisms. Parotid, submaxillary-sublingual, and whole salivas will be collected from human donor. Glycoproteins will then be isolated, characterized with respect to their number of subunits and chemical composition, and tested for their ability to aggregate selected oral microorganisms. The aggregating glycoproteins will then be modified by proteases and specific glycosidases and subsequently tested for aggregating ability. By these procedures the specificity of the salivary-bacterial interaction will be ascertained.